Blockages and obstructions can develop in certain areas of the body, such as in the kidneys, pancreas, esophagus, and gallbladder. Minimally invasive medical procedures generally cause limited trauma to the tissue of a patient and can be used to eliminate problematic obstructions. Lithotripsy and ureteroscopy, for example, are used to treat urinary calculi, e.g., kidney stones, in the ureter of patients.
Lithotripsy is a medical procedure that uses energy in various forms, such as acoustic or electrical shock waves, pneumatic or hydraulic pulsation, or laser beams, to break up biological concretions, such as urinary calculi. The force of the energy, when applied either extracorporeally or intracorporeally, usually in focused and continuous or successive bursts, comminutes a kidney stone into smaller fragments that may be extracted from the body or allowed to pass through urination. With the help of imaging tools, such as transureteroscopic video technology and fluoroscopic imaging, the operator of the lithotripter device can monitor the progress of the medical procedure and terminate treatment when residual fragments are small enough to be voided or removed. Examples of such obstructions and the effects of treatment can be found in the published patent application US 2001/0031971, the disclosure of which is incorporated by reference herein in its entirety.
Intracorporeal fragmentation of urinary calculi can prove problematic, because stones and/or stone fragments in the ureter may become repositioned closer to and possibly migrate back toward the kidney, thereby requiring further medical intervention to prevent aggravation of the patient's condition.
Many known stone extraction devices are rigid and lack the maneuverability and flexibility to engage and disengage repeatedly a stone without harming the surrounding tissue. For example, if a stone is still too large to be extracted without further fragmentation, it can be difficult to disengage the stone from such an extraction device without damaging the delicate lining of the ureteral wall.